Microsoft BackOffice 4.0 and 4.5, when configured to be accessible by other systems, allows remote attackers to bypass authentication and access the administrative ASP pages via an HTTP request with an authorization type (auth_type) that is not blank.
http://www.securityfocus.com/bid/4528
http://www.iss.net/security_center/static/8862.php
http://support.microsoft.com/support/kb/articles/q316/8/38.asp
http://archives.neohapsis.com/archives/bugtraq/2002-04/0208.html